Deal for Dorsey: NT signs two-year extension

The 49ers don’t know when – or if – they’ll have the services of Glenn Dorsey this season.

But now they know they’ll have the rights to their nose tackle through 2016 after they signed Dorsey, 29, to a two-year contract extension today. Terms of the deal were not immediately known.

Dorsey tore his biceps on Aug. 1 in practice and it’s not known how long he’ll be sidelined. The 49ers could place Dorsey on injured reserve with the designation to return at some point after the first eight regular-season games.

“Glenn is a true pro who has quickly become a valued contributor to our organization both on and off the field,” general manager Trent Baalke said. “He is a quick study and a very good football player that has earned this extension, and we look forward to his future contributions.”

Dorsey, the No. 5 pick in 2008, was entering the final year of a contract that will pay him a $2.3 million base salary this season. The 49ers signed him last year and he blossomed inside after spending his first five seasons as a defensive end with the Chiefs.

Dorsey, 6-foot-1 and 297 pounds, made 13 starts and collected 41 tackles and two sacks for a defense that ranked fourth in the NFL in rushing yards allowed. He assumed the starting role after Ian Williams sustained a severe ankle injury in Week 2. Williams, who was activated from the physically unable to perform list last week, is the leading candidate to start in Week 1. Williams is signed through 2015.